Rechargeable battery and pack of the same

ABSTRACT

An aspect of the present invention provides a rechargeable battery which makes placement of the electrode assembly in the case during assembly easy. The rechargeable battery includes an electrode assembly including a first electrode, a separator, and a second electrode, a case housing the electrode assembly and having an opening in a plane parallel to a flat side surface of the electrode assembly, the case being electrically connected to the first electrode, a cover closing the opening in the case, and an electrode terminal mounted to a terminal opening in the case and connected to the second electrode, wherein the electrode terminal and the second electrode are insulated from the case.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2015-0006990 filed in the Korean IntellectualProperty Office on Jan. 14, 2015, the entire contents of which areincorporated herein by reference.

BACKGROUND

1. Field

This description relates to a rechargeable battery and a battery packincluding the same.

2. Description of the Related Art

Unlike a primary battery, a rechargeable battery is designed forrepeated charging and discharging. A small capacity rechargeable batterymay be used in a small portable electronic device, such as a mobilephone, a laptop computer and a camcorder, and a large capacityrechargeable battery may be used as a power source of a motor in ahybrid vehicle or an electric vehicle.

As an example, a rechargeable battery may include an electrode assemblyfor charging and discharging, a case for housing the electrode assembly,a cap plate coupled to an opening in the case, and an electrode terminaloutside of the cap plate.

The rechargeable battery is assembled as the electrode terminal isconnected to the electrode assembly and mounted to the cap plate, andthe cap plate is welded to the case after the electrode assembly isplaced in the case. The case has an opening formed at a narrow (orsmall) side of a substantially rectangular shaped case, and theelectrode assembly is placed in the case through the opening.

Therefore, when the electrode assembly is placed in the case, theelectrode assembly may be damaged by the opening of the case. That is,safely placing the electrode assembly in the case during assembly of thesecondary battery is difficult.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form prior art.

SUMMARY

The present invention provides a rechargeable battery and a pack of thesame. The rechargeable battery includes an electrode assembly that maybe easily placed in a case, wherein the battery pack may be easilyassembled.

An aspect of the present invention provides a rechargeable battery whichenables easy placement of an electrode assembly in a case. Anotheraspect of the present invention provides a rechargeable battery packwhich may be easily assembled.

In accordance with one or more embodiments of the present invention, arechargeable battery includes: an electrode assembly including a firstelectrode, a separator and a second electrode; a case housing theelectrode assembly and having an opening in a plane parallel to a flatside surface of the electrode assembly, the case being electricallyconnected to the first electrode; a cover closing the opening in thecase; and an electrode terminal electrically mounted to a terminalopening in the case and connected to the second electrode, wherein theelectrode terminal and the second electrode are insulated from the case.

The first electrode, the separator, and the second electrode may bestacked and spirally wound.

The case may include a bottom for supporting a flat portion of theelectrode assembly, the bottom being opposite to the opening, and a sidewall extending from the bottom along a periphery of the bottom.

The side wall may include a first long side wall and a second long sidewall parallel to the first long side wall, and a first short side walland a second short side wall parallel to the first short side wall, thefirst short side wall and the second short side wall each connected tothe first long side wall and the second long side wall, and the firstlong side wall may have a terminal opening formed therein.

The electrode assembly may have spirally-wound end portions that facethe first short side wall and the second short side wall, respectively.

The rechargeable battery may further include a first lead tab connectedto the first electrode of the electrode assembly and connected to aninside surface of the first long side wall by welding.

The first long side wall may further include a welding inducing portionprotruded toward the first lead tab from an inside surface thereof andwelded to the first lead tab.

The electrode terminal may include a plate terminal on an outside of thelong side wall and aligned with the terminal hole, and a rivet terminalconnected to the electrode assembly via a second lead tab extendingthrough the terminal opening and fastened to the plate terminal.

The rechargeable battery may further include an insulating memberbetween the plate terminal and one of the long side walls, and a gasketbetween the rivet terminal and the terminal opening.

The electrode assembly may have spirally-wound end portions facing thefirst long side wall.

The rechargeable battery may further include an insulating plate betweenthe first long side wall and the electrode assembly, wherein the firstelectrode has an uncoated portion connected to an inside surface of thefirst long side wall via a first lead tab, and wherein the secondelectrode has an uncoated portion connected to the electrode terminalwith a second lead tab.

The first long side wall may further include a welding inducing portionprotruded toward the first lead tab from an inside surface of the firstlong side wall and welded to the first lead tab.

The electrode terminal may include a plate terminal on an outside of thefirst long side wall corresponding to the terminal opening, and a rivetterminal connected to the electrode assembly via a second lead tab,extending through the terminal opening, and fastened to the plateterminal.

The rechargeable battery may further include an insulating memberbetween the plate terminal and the first long side wall, and a gasketbetween the rivet terminal and the terminal hole.

According to another aspect of the present invention, a rechargeablebattery pack includes a plurality of unit cells, each one of the unitcells having an electrode assembly with a first electrode electricallyconnected to a case, the case having an opening in a plane parallel to aflat side surface of the electrode assembly and a second electrodeelectrically connected to an electrode terminal, the electrode terminalextending away from the case and insulated from the case, and a bus barconnected between the electrode terminal of a first unit cell of theunit cells and the case of a second unit cell of the unit cells, theelectrode terminal of the first cell having a height that is differentfrom a height of the case of the second unit cell.

The case may have a first long side wall, a second long side wall, afirst short side wall and a second short side wall, each side wallconnected to a bottom of the case, thereby forming the opening, theopening being opposite to the bottom, wherein the bus bar is connectedto the first long side wall.

The bus bar may be connected to a bus bar connection recess recessed inthe first long side wall of the case of the second unit cell.

The bus bar may be connected to the first long side wall of the case ofthe second unit cell by welding.

Because the rechargeable battery of the present invention has a wideopening in the case which intersects a plane parallel to a flat sidesurface of the electrode assembly, the electrode assembly may be placedin the case through the wide opening, making assembly of therechargeable battery easy.

Because the rechargeable battery pack of the present invention has a busbar having a height difference and connecting an electrode terminal of afirst unit cell and the case of a second unit cell adjacent to the firstunit cell, assembly of the pack may be easy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a rechargeable battery in accordancewith a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the rechargeable battery ofFIG. 1.

FIG. 3 is a cross-sectional view taken along the line of III-III of FIG.1.

FIG. 4 is an exploded perspective view of a rechargeable battery inaccordance with a second embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 4.

FIG. 6 is a perspective view of a rechargeable battery pack inaccordance with a first embodiment of the present invention.

FIG. 7 is a cross-sectional view taken along the line VII-VII of FIG. 6.

FIG. 8 is a cross-sectional view of a rechargeable battery pack inaccordance with a second embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention are described more fullyhereinafter with reference to the accompanying drawings, such that aperson of ordinary skill in the relevant art can easily carry out thepresent invention. However, the present invention may be embodied indifferent modes, and is not limited to the description of embodimentsmade herein. Parts not relevant to the present invention may be omittedto enhance clarity of the disclosure, and throughout the specification,identical or similar parts have the same reference numbers.

Accordingly, the embodiments are described below as examples only, byreferring to the figures, to explain aspects of the embodiments of thepresent invention. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.Expressions such as “at least one of,” when preceding a list ofelements, modify the entire list of elements and do not modify theindividual elements of the list.

It will be understood by a person of ordinary skill in the art that,although the terms ‘first’ and ‘second’ are used herein to describevarious elements, these elements should not be limited by these terms.Instead, these terms are only used to distinguish one element fromanother element. It will be further understood by a person of ordinaryskill in the art that the terms “comprises” and/or “comprising,” whenused in this specification, specify the presence of stated features,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise.

FIG. 1 is a perspective view of a rechargeable battery in accordancewith a first embodiment of the present invention, and FIG. 2 is anexploded perspective view of the rechargeable battery of FIG. 1.Referring to FIGS. 1 and 2, a rechargeable battery 1 includes anelectrode assembly 10 for charging and discharging a current, a case 15for housing the electrode assembly 10 therein, and an electrode terminal21 mounted in a terminal opening H (e.g., a terminal hole) in the case15 and electrically connected to the electrode assembly 10.

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1.Referring to FIGS. 2 and 3, the electrode assembly 10 has a tabularshape and is housed in the case 15. The electrode assembly 10 includes afirst electrode 11 (also referred to herein as a “positive electrode”)and a second electrode 12 (also referred to herein as a “negativeelectrode”) arranged on either side of a separator 13 and spiral-woundin a jelly roll state. The separator 13 may be an insulator.

The positive and negative electrodes 11, 12 respectively include acoated portion 11 a, 12 a having an active material coated on a currentcollector of a metal foil (for example, an Al or Cu foil) and anuncoated portion 11 b, 12 b having no active material coated thereonthereby exposing the current collector.

The uncoated portion 11 b of the positive electrode 11 is formed on aside end portion of the positive electrode 11 along the spirally-woundpositive electrode 11. The uncoated portion 12 b of the negativeelectrode 12 is formed on a side end portion of the negative electrode12 along the spirally-wound negative electrode 12. The uncoated portions11 b and 12 b are arranged on opposite sides of the electrode assembly10, respectively.

The case 15 may have a substantially rectangular hexahedral shape havingan open side (e.g., having an opening) to form a space for housing theelectrode assembly 10. The opening in the case 15 is formed in a plane(e.g., a x-y plane) parallel to a flat side surface of the electrodeassembly 10. That is, the opening is formed in a wide side of the case15, as illustrated in FIG. 2.

Therefore, the electrode assembly 10 may be placed in the case 15 in afirst direction (e.g., a z-axis direction) which intersects the firstplane (or the x-y plane). As such, because the electrode assembly 10 isplaced in the wide opening of the case 15, placement of the electrodeassembly 10 in the case 15 becomes relatively easy.

The case 15 may have a bottom 16 for supporting a flat portion of theelectrode assembly 10 on a side opposite to the rectangular opening anda side wall 17 having a height in the first direction (or the z-axisdirection) and extending from an outside periphery of the bottom 16. Thebottom 16 is formed in a rectangular shape and substantially matches (orcorresponds to) the flat portion of the electrode assembly 10, and theside wall 17 substantially matches (or corresponds to) the height of theelectrode assembly 10 in the first direction (or the z-axis direction).

The side wall 17 includes a first long side wall 171 and a second longside wall 172 parallel to the first long side wall 171 and a first shortside wall 173 and a second short side wall 174 parallel to the secondshort side wall 173, the first short side wall 173 and the second shortside wall 174 each connected to the first long side wall 171 and thesecond long side wall 172. The first and second short side walls 173 and174 may extend in a second direction (or the x-axis direction) and thefirst and second long side walls 171 and 172 may extend in a thirddirection (e.g., a y-axis direction), wherein the second direction andthe third direction intersect with each other. The first and second longside walls 171 and 172 are formed relatively longer than the first andsecond short side walls 173 and 174. The first long side wall 171 has aterminal opening H (e.g., a terminal hole) formed therein for mountingthe electrode terminal 21.

When the electrode assembly 10 is inserted into the case 15, the case 15and the positive electrode 11 are electrically connected to each other.For example, the positive electrode 11 may be directly electricallyconnected to an inside surface of the first long side wall 171. Theelectrode assembly 10 is housed in the case 15 such that the flatportion of the electrode assembly 10 faces the bottom 16. Accordingly,the spiral-wound end portions of the electrode assembly 10 face thefirst and second short side walls 173 and 174.

The first long side wall 171 of the case 15 has at least one opening,for example, the first long side wall 171 may have an electrolyteinjection opening 29 and a vent hole 24. The electrolyte injectionopening 29 enables injection of an electrolyte into the case 15 aftercoupling and welding a cover 20 to the case 15. After injecting theelectrolyte, the electrolyte injection opening 29 is closed with asealing plug 27.

The vent hole 24 is closed with a vent plate 26. The vent hole 24 may beused to discharge a gas generated in the rechargeable battery 1 duringcharging and discharging of the electrode assembly 10, as well asrelease (or discharge) an internal pressure caused by the gas.

If the internal pressure of the rechargeable battery 1 reaches a presetpressure, the vent plate 26 of the vent hole 24 is cut open to dischargethe gas and reduce the internal pressure of the rechargeable battery 1.The vent plate 26 may have a notch for inducing the cut.

The cover 20 is mounted to the opening of the case 15 to tightly closethe case 15. For example, the case 15 and the cover 20 made of aluminummay be welded together at the opening of the case.

The positive electrode 11 of the electrode assembly 10 may beelectrically connected to the first long side wall 171 of the case 15through a first lead tab 181 (also referred to herein as a positiveelectrode lead tab). For example, the positive electrode lead tab 181may be directly connected to the inside surface of the first long sidewall 171 by welding.

The first long side wall 171 may have a welding inducing portion 175 atan inside surface that protrudes toward the positive electrode lead tab181, thereby enabling welding and connection to the positive electrodelead tab 181. Therefore, the case 15 and the cover 20 in therechargeable battery 1 are each charged as a positive electrode. Thecase 15 thus functions as a positive electrode terminal.

The welding inducing portion 175 is formed inside a recessed portion ofthe first long side wall 171 of the case 15. For example, an outside ofthe welding inducing portion 175 forms a bus bar connection recess 176to which one side of a bus bar 3 (See FIGS. 6 and 7) may be connectedduring assembly of a rechargeable battery pack 100.

The negative electrode 12 of the electrode assembly 10 is electricallyconnected to the electrode terminal 21 mounted in the terminal opening Hin the first long side wall 171 through a second lead tab 182 (alsoreferred to herein as a negative electrode lead tab). The electrodeterminal 21 functions as a negative electrode terminal.

The electrode terminal 21 may include a plate terminal 21 c arranged atthe outside of the first long side wall 171 and corresponding to (oraligned with) the terminal opening H, and a rivet terminal 21 a mountedto the first long side wall 171, the rivet terminal 21 a passing throughthe terminal opening H and electrically connected to the electrodeassembly 10 and fastened to the plate terminal 21 c.

The plate terminal 21 c has a through-hole H3 and the rivet terminal 21a passes through the terminal opening H and an upper portion of therivet terminal 21 a passes through the through-hole H3. The rivetterminal 21 a includes a column portion 211 that extends through theterminal opening H in the first long side wall 171, and a flange portion212 formed on one end of the column portion 211. The flange portion 212is arranged (or aligned) at an inside of the first-long side wall 171and is formed to have a larger area than a cross-section of the columnportion 211.

A gasket 36 is mounted between the column portion 211 of the rivetterminal 21 a and an inside surface of the terminal opening H in thefirst long side wall 171 for sealing and electrically insulating thecolumn portion 211 of the rivet terminal 21 a and the terminal opening Hin the first long side wall 171.

The gasket 36 extends between the flange portion 212 and the insidesurface of the first long side wall 171 for sealing and electricallyinsulating the flange portion 212 from the first long side wall 171. Assuch, when the electrode terminal 21 is mounted to the first long sidewall 171, the gasket 36 prevents the electrolyte from leaking throughthe terminal opening H.

The positive and negative electrode lead tabs 181 and 182 respectivelyelectrically connect the first long side wall 171 and the electrodeterminal 21 to the positive and negative electrodes 11 and 12 of theelectrode assembly 10. That is, the positive and negative electrode leadtabs 181 and 182 are respectively connected to the first long side wall171 and the rivet terminal 21 a on one side, and are respectivelyconnected to the uncoated portions 11 b and 12 b of the electrodeassembly 10 by welding on the other side.

As the column portion 211 of the rivet terminal 21 a is placed in acoupling hole 511 in the negative electrode lead tab 182, and the flangeportion 212 supports the surroundings of the coupling hole 511, therivet terminal 21 a is electrically connected to the negative electrodelead tab 182. A periphery of the column portion 211 and the couplinghole 511 may be subjected to caulking or welding.

An insulating member 31 is placed between the plate terminal 21 c andthe first long side wall 171 for electrically insulating the plateterminal 21 c from the first long side wall 171. That is, the first longside wall 171 and the case 15 are insulated from the electrode terminal21.

The insulating member 31 and the plate terminal 21 c are fastened to atop side of the rivet terminal 21 a by riveting or welding, for example.The plate terminal 21 c is mounted to an outside of the first long sidewall 171 with the insulating member 31 interposed therebetween.

The following description refers to a rechargeable battery in accordancewith a second embodiment of the present invention. Description ofconfigurations that are identical to those of the first embodiment ofthe present invention may be omitted, and different configurations areprimarily described below.

FIG. 4 illustrates an exploded perspective view of a rechargeablebattery in accordance with a second embodiment of the present invention,and FIG. 5 illustrates a cross-sectional view taken along the line V-Vof FIG. 4. Referring to FIGS. 4 and 5, according to a second embodimentof the present invention, a rechargeable battery 2 has spirally-woundend portions of an electrode assembly 210 that face the first long sidewall 171.

Even when the spiral-wound end portions of the electrode assembly 210face the first long side wall 171, because the first plane (e.g., thex-y plane) of the electrode assembly 210 is aligned in the firstdirection (e.g., the z-axis direction), which intersects the wideopening of the case 15, placement of the electrode assembly 210 in thecase 15 during assembly becomes easy.

In addition, the rechargeable battery 2 in accordance with the secondembodiment of the present invention further includes an insulating plate60 mounted between the first long side wall 171 and the electrodeassembly 210. The insulating plate 60 is arranged on (or along) aninside surface of the first long side wall 171 for insulating the firstlong side wall 171 from the electrode assembly 210.

The insulating plate 60 has an internal vent hole 604 that correspondsto (or is aligned with) the vent hole 24 in the case 15. Because theinternal vent hole 604 corresponds to the vent hole 24 in the first longside wall 171, the internal vent hole 604 may transmit internal pressuregenerated in the electrode assembly 210 to the vent hole 24 anddischarge it therefrom.

The insulating plate 60 has an internal electrolyte injection opening605 that corresponds to (or is aligned with) the electrolyte injectionopening 29 in the case 15. Since the internal electrolyte injectionopening 605 corresponds to the electrolyte injection opening 29 in thefirst long side wall 171, the electrolyte may be injected to the insideof the insulating plate 60 through the electrolyte injection opening 29.

The uncoated portions 111 and 121 of the electrode assembly 210 arehoused in the case 15. The uncoated portion 111 is electricallyconnected to the first long side wall 171 via a through-hole 601 in theinsulating plate 60, and the uncoated portion 121 is electricallyconnected to an electrode terminal 61 via a through-hole 602 in theinsulating plate 60.

The uncoated portion 111 of the positive electrode is connected (e.g.,welded) to an internal surface of the first long side wall 171 with apositive electrode lead tab 515 provided between the insulating plate 60and the first long side wall 171. The uncoated portion 121 of thenegative electrode 12 is connected to the electrode terminal 61 with anegative electrode lead tab 525 provided between the insulating plate 60and the first long side wall 171.

The positive electrode lead tab 515 may be welded to the weldinginducing portion 175 protruded from the inside wall of the first longside wall 171.

Therefore, in the rechargeable battery 2, the case 15 and the cover 20are both charged as a positive electrode. The case 15 functions as apositive electrode terminal. The outside surface of the welding inducingportion 175 has a bus bar connection recess 176 that connects to oneside of a bus bar during fabrication or assembly of the rechargeablebattery pack.

The negative electrode lead tab 525 may be welded to a rivet terminal611 of the electrode terminal 61 between the insulating plate 60 and thefirst long side wall 171 (i.e., the negative electrode tab 525 isbetween the rivet terminal 611 and the insulating plate 60, and therivet terminal 611 is between the negative electrode tab 525 and thefirst long side wall 171). The rivet terminal 611 may extend through theterminal opening H and may be connected to a plate terminal 612. Theelectrode terminal 61 functions as a negative terminal. The insulatingmember 31 is interposed between the plate terminal 612 and the firstlong side wall 171, and a gasket 236 is interposed between the rivetterminal 611 and the terminal opening H.

The following description refers to a rechargeable battery pack having arechargeable battery in accordance with one or more embodiments of thepresent invention. Descriptions of configurations that are identical tothose of the rechargeable battery described above may be omitted.

FIG. 6 illustrates a perspective view of a rechargeable battery pack inaccordance with a first embodiment of the present invention, and FIG. 7illustrates a cross-sectional view taken along the line VII-VII of FIG.6. For convenience of description, the rechargeable battery pack 100 isdescribed as having the rechargeable battery 1 described above withreference to a first embodiment of the present invention. Referring toFIGS. 6 and 7, the rechargeable battery pack 100 may include a pluralityof unit cells (e.g., a first unit cell 101, a second unit cell 102 and athird unit cell 103) and a bus bar 3 electrically connecting the first,second, and third unit cells 101, 102, and 103.

In one or more embodiments, a height difference ΔH1 may exist betweenthe electrode terminal 21 of the first unit cell 101 and the case 15 ofthe second unit cell 102 (e.g., a height difference ΔH1 between the busbar connection recess 176 and the outer surface of the electrodeterminal 21 may be predetermined). The bus bar 3 may connect theelectrode terminal 21 of the first unit cell 101 to the case 15 of thesecond unit cell 102 with the height difference ΔH1.

The bus bar 3 may be connected to the first long side wall 171 of thecase 15, and may be bent to have the height difference ΔH1. The bus bar3 is connected to the bus bar connection recess 176 that is recessedfrom the first long side wall 171 of the case 15 of the second unit cell102.

For example, the bus bar 3 may have one end placed in and welded to thebus bar connection recess 176. Thus, by connecting bus bars 3 having theheight difference ΔH1 to the electrode terminals 21 and the cases 15 ofthe first and second unit cells 101 and 102 adjacent to one another, theneed to align the bus bars 3 is greatly reduced and pack assembly maybecome relatively easy.

FIG. 8 illustrates a cross-sectional view of a rechargeable battery packin accordance with a second embodiment of the present invention.Referring to FIG. 8, in a rechargeable battery pack 200, a heightdifference ΔH2 may exist between the electrode terminal 21 of a firstunit cell 201 and the case 25 of a second unit cell 202. A bus bar 23may be connected between the electrode terminal 21 of the first unitcell 201 and the case 25 of the second unit cell 202 with the heightdifference ΔH2.

For example, the bus bar 23 may be welded to a first long side wall 191of the case 25 and be bent to have the height difference ΔH2.

Although the rechargeable battery and the rechargeable battery pack inaccordance with example embodiments of the present invention have beendescribed, the present invention is not limited thereto, and variationsand modifications are possible within the scope of the claims, detaileddescription of the present invention, and accompanying drawings.

While this invention has been described in connection with what ispresently considered to be some practical exemplary embodiments, it isto be understood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims and their embodiments.

DESCRIPTION OF SOME OF THE REFERENCE SYMBOLS

-   1, 2: rechargeable battery-   3, 23: bus bar-   10, 210: electrode assembly-   11: first electrode (positive electrode)-   11 a, 12 a: coated portion-   11 b, 12 b, 111, 121: uncoated portion-   12: second electrode (negative electrode)-   15, 25: case-   16: bottom-   17: side wall-   20: cover-   21, 61: electrode terminal-   21 a, 611: rivet terminal-   21 c, 612: plate terminal-   24: vent hole-   26: vent plate-   27: seal plug-   29: electrolyte injection opening-   31: insulating member-   36: gasket-   60: insulating plate-   100, 200: rechargeable battery pack-   101, 102, 103: first, second, and third unit cells-   171, 191: first long side wall-   172: second long side wall-   173, 174: first and second short side walls-   175: welding inducing portion-   176: bus bar connection recess-   181, 515: first lead tab (positive electrode lead tab)-   182, 525: second lead tab (negative electrode lead tab)-   211: column portion-   212: flange portion-   601, 602: pass through opening-   604: inside vent hole-   605: internal electrolyte injection opening-   H: terminal opening-   H3: through-hole-   ΔH1, ΔH2: height difference

What is claimed is:
 1. A rechargeable battery comprising: an electrodeassembly comprising a first electrode, a separator, and a secondelectrode; a case comprising a first long side wall, the case housingthe electrode assembly and having an opening in a first plane parallelto a flat side surface of the electrode assembly, the case beingelectrically connected to the first electrode; a cover welded to thecase at the opening in the case and closing the opening in the case; andan electrode terminal electrically mounted to a terminal opening in thefirst long side wall of the case and connected to the second electrode,the electrode terminal being at a first side of the first long sidewall, wherein the electrode terminal and the second electrode areinsulated from the case, wherein the terminal opening is spaced apartfrom the opening in the case, wherein the terminal opening and theopening in the case are defined in intersecting planes, wherein thefirst long side wall comprises a vent and a bus bar connection portionat a second side of the first long side wall opposite to the first sideof the first long side wall, wherein a first distance between a portionof the electrode terminal that is furthest from the electrode assemblyand the electrode assembly in a first direction parallel to the firstplane is greater than a second distance between a portion of the firstlong side wall that is furthest from the electrode assembly and theelectrode assembly in the first direction, and wherein a third distancebetween the bus bar connection portion and the electrode assembly isless than the first distance.
 2. The rechargeable battery of claim 1,wherein the first electrode, the separator, and the second electrode ofthe electrode assembly are stacked and spirally wound.
 3. Therechargeable battery of claim 1, wherein the case comprises a bottom forsupporting a flat portion of the electrode assembly, the bottom beingopposite to the opening in the case, and wherein the first long sidewall is a part of a side wall that extends from the bottom along aperiphery of the bottom.
 4. The rechargeable battery of claim 3, whereinthe side wall further comprises: a second long side wall parallel to thefirst long side wall; and a first short side wall and a second shortside wall parallel to the first short side wall, the first short sidewall and the second short side wall each connected to the first longside wall and the second long side wall.
 5. The rechargeable battery ofclaim 4, wherein the electrode assembly has spirally-wound end portionsthat face the first short side wall and the second short side wall,respectively.
 6. The rechargeable battery of claim 4, further comprisinga first lead tab connected to the first electrode of the electrodeassembly and connected to an inside surface of the first long side wallby welding.
 7. The rechargeable battery of claim 6, wherein the firstlong side wall further comprises a welding inducing portion protrudedtoward the first lead tab from an inside surface thereof and welded tothe first lead tab.
 8. The rechargeable battery of claim 4, wherein theelectrode terminal comprises: a plate terminal on an outside of thefirst long side wall and aligned with the terminal opening; and a rivetterminal connected to the electrode assembly via a second lead tab,extending through the terminal opening, and fastened to the plateterminal.
 9. The rechargeable battery of claim 8, further comprising: aninsulating member between the plate terminal and one of the long sidewalls from among the first long side wall and the second long side wall;and a gasket between the rivet terminal and the terminal opening. 10.The rechargeable battery of claim 4, wherein the electrode assembly hasspirally-wound end portions facing the first long side wall.
 11. Therechargeable battery of claim 10, further comprising an insulating platebetween the first long side wall and the electrode assembly, wherein thefirst electrode has an uncoated portion connected to an inside surfaceof the first long side wall via a first lead tab, and wherein the secondelectrode has an uncoated portion connected to the electrode terminalwith a second lead tab.
 12. The rechargeable battery of claim 11,wherein the first long side wall further comprises a welding inducingportion protruded toward the first lead tab from an inside surface ofthe first long side wall and welded to the first lead tab.
 13. Therechargeable battery of claim 11, wherein the electrode terminalcomprises: a plate terminal arranged on an outside of the first longside wall corresponding to the terminal opening; and a rivet terminalconnected to the electrode assembly via a second lead tab extendingthrough the terminal opening and fastened to the plate terminal.
 14. Therechargeable battery of claim 13, further comprising: an insulatingmember between the plate terminal and the first long side wall; and agasket between the rivet terminal and the terminal opening.
 15. Therechargeable battery of claim 1, wherein the bus bar connection portioncomprises a connection recess that is inwardly depressed from the firstlong side wall toward the electrode assembly.